Before our invention current shaped metal package manufacturing was both very complex and costly when compared to the manufacture of a standard straight walled metal can. In addition, additional process input metal is required when drawn and ironed (D&I) cylinders are used in the process of shaping metal packages. The additional input metal is needed to compensate for cylinder wall thinning as the cylinder is stretched and shaped during the forming process. As a consequence, the additional input metal in the form of a thicker walled metal sheet leads to heavier sidewall metal thicknesses. Though required due in part to the extensive metal work required to stretch, shape, and then trim the metal package, this is an undesirable result of the drawn and ironed process and increases metal packaging costs and manufacturing complexities.
In addition, there are numerous limitations of the drawn and ironed process when used for shaped metal packages. One such limitation is that the drawn and ironed process can only produce symmetrically shaped configurations around the shaped metal body. Another limitation is that added steps to the drawn and ironed process must often be added, such as additional necking with longer stroke length, to shape the metal package to a final form. Another limitation with respect to reforming is that the process is limited by the shaped metal package maximum expansions, for aluminum this is typically in the range of 8-10% of the ironed can sidewalls.
These shortcomings and limitations in effect limit the use of the drawn and ironed techniques in shaped metal packaging and as such limits the uses of shaped metal packaging in the marketplace and within the beverage and food industry to only premium price point beverage and food products and locations. There is a long felt need for a low cost high speed shaped metal vessel manufacturing method to create metal vessels that use less metal, and overcome the limitations mentioned above as well as overcome other limitations, which gives rise to the present invention.